A composite material having heat dissipation and flame retardant properties, a method of making the same, and a battery module comprising the same

Abstract

A method for manufacturing a composite material having heat dissipation and flame retardant properties according to the present invention may include the steps of: preparing a polymer, an endothermic flame retardant material, and a flame retardant and heat dissipation multifunctional material; mixing the polymer, the endothermic flame retardant material, and the flame retardant and heat dissipation multifunctional material while applying a shear force at a first temperature to produce a composite material source; and applying a first pressure to the composite material source to produce a composite material.

Description

Technology Field

[0001] The present invention relates to a composite material having heat dissipation and flame retardant properties, a method for manufacturing the same, and a battery module including the same. More specifically, the invention relates to a composite material comprising an endothermic flame retardant material and a flame retardant and heat dissipation multifunctional material within a polymer matrix, a method for manufacturing the same, and a battery module including the same. Background Technology

[0002] A heat-dissipating composite material refers to a material capable of conducting heat by using two or more materials selected from polymers, ceramics, or metals.

[0003] Thermal conduction in heat dissipation composite materials occurs in a stage where heat generated from a specific device is conducted by the thermally conductive material of the composite, thereby releasing the heat generated from the specific device.

[0004] Accordingly, heat dissipation composite materials can be utilized in various industries, such as LED headlamps, computer CPUs and motherboards, displays, mobile phone batteries, and electric vehicles.

[0005] As application fields increase, heat dissipation composite materials with high heat dissipation characteristics are being researched. For example, Korean Patent Publication No. 10-179767 describes a method for manufacturing a silver-carbon nanocomposite for a heat dissipation material, comprising: a first step of preparing a mixed powder by mixing graphite powder and silver powder in a predetermined ratio; and a second step of forming a silver-carbon nanocomposite by irradiating the mixed powder with microwaves under a predetermined gas atmosphere. Prior to the first step, the method further comprises a step of pre-treating the graphite powder by a method selected from microwave treatment or plasma treatment. In the second step, by irradiating with microwaves, the graphite powder is exfoliated to form graphene, and the graphene reacts with the silver powder to form a silver-carbon nanocomposite having a structure in which silver particles grow into nanoparticles on the surface of the graphene. Furthermore, the mixed powder is self-heated to a temperature of 400 to 1700 ℃ by the microwaves irradiated in the second step to form the silver-carbon nanocomposite. The thermal diffusivity is 140 to 170 mm 2 A method for manufacturing a silver-carbon nanocomposite for heat dissipation materials is disclosed, characterized by having a silver-carbon nanocomposite with a Vickers hardness of 70 to 140 HV. The problem to be solved

[0006] The technical problem that the present invention aims to solve is to provide a method for manufacturing a composite material with improved heat dissipation properties.

[0007] Another technical problem that the present invention aims to solve is to provide a method for manufacturing a composite material with improved flame-retardant properties.

[0008] Another technical problem that the present invention aims to solve is to provide a method for manufacturing a composite material with reduced manufacturing process costs.

[0009] Another technical problem that the present invention aims to solve is to provide a method for manufacturing a composite material with reduced manufacturing time.

[0010] Another technical problem that the present invention aims to solve is to provide a method for manufacturing a composite material that is easy to mass-produce.

[0011] The technical problems that the present invention aims to solve are not limited to those described above. means of solving the problem

[0012] To solve the above technical problem, the present invention provides a method for manufacturing a composite material.

[0013] According to one embodiment, the method for manufacturing the composite material may include the steps of: preparing a polymer, an endothermic flame-retardant material, and a flame-retardant and heat-dissipating multifunctional material; mixing the polymer, the endothermic flame-retardant material, and the flame-retardant and heat-dissipating multifunctional material while applying a shear force at a first temperature to produce a composite material source; and applying a first pressure to the composite material source to produce the composite material.

[0014] According to one embodiment, the polymer may have a first glass transition temperature and a second glass transition temperature higher than the first glass transition temperature, and the first temperature may be at least the first glass transition temperature.

[0015] According to one embodiment, in the step of manufacturing the composite material source, the polymer is transformed into a polymer matrix having a three-dimensional network structure by the shear force applied at the first temperature, and the heat-endostimulating flame-retardant material and the flame-retardant and heat-dissipating multifunctional material may be dispersed within the polymer matrix.

[0016] According to one embodiment, in the step of manufacturing the composite material source, the shear force may be 50 Nm or more.

[0017] According to one embodiment, in the step of manufacturing the composite material, the first pressure may be 10 Pa to 50 MPa.

[0018] To solve the above technical problem, the present invention provides a composite material manufactured by the manufacturing method described above.

[0019] According to one embodiment, the composite material may include a polymer matrix having a three-dimensional network structure, an endothermic flame-retardant material dispersed within the polymer matrix that absorbs heat and suppresses flames above a reference temperature, and a flame-retardant and heat-dissipating multifunctional material dispersed within the polymer matrix that releases heat and expands above a reference temperature to block incoming oxygen.

[0020] According to one embodiment, the weight ratio of the polymer matrix may be 5 wt% or more, and the weight ratio of the heat-absorbing flame-retardant material and the flame-retardant and heat-dissipating multifunctional material may be 95 wt% or less.

[0021] According to one embodiment, the polymer matrix comprises polytetrafluoroethylene, the heat-endothermic flame retardant material comprises any one of magnesium hydroxide, aluminum hydroxide, antimony trioxide, or antimony pentoxide, and the flame retardant and heat-dissipating multifunctional material may comprise any one of carbon nanotubes, expandable graphite (graphene), or carbon black.

[0022] To solve the above technical problem, the present invention provides a battery module to which the above-described composite material is applied.

[0023] According to one embodiment, the battery module comprises the composite material described above, a case surrounded by the composite material, and a battery cell surrounded by the case, and at a temperature above a reference temperature, the heat-absorbing flame-retardant material of the composite material absorbs heat to suppress flames, and the flame-retardant and heat-dissipating multifunctional material of the composite material releases heat and expands simultaneously to block incoming oxygen.

[0024] According to one embodiment, the battery module comprises the composite material, a battery cell surrounded by the composite material, and a case surrounding the composite material, and at a temperature above a reference temperature, the heat-absorbing flame-retardant material of the composite material absorbs heat to suppress flames, and the flame-retardant and heat-dissipating multifunctional material of the composite material releases heat and expands simultaneously to block incoming oxygen.

[0025] According to one embodiment, the battery module comprises the composite material, a first case surrounded by the composite material, a battery cell surrounded by the first case, and a second case surrounding the composite material, and at a temperature above a reference temperature, the heat-absorbing flame-retardant material of the composite material absorbs heat to suppress a flame, and the flame-retardant and heat-dissipating multifunctional material of the composite material releases heat and expands simultaneously to block incoming oxygen. Effects of the invention

[0026] A method for manufacturing a composite material according to an embodiment of the present invention may include the steps of: mixing a polymer, an endothermic flame-retardant material, and a flame-retardant and heat-dissipating multifunctional material while applying a shear force at a first temperature to produce a composite material source; and applying the first pressure to the composite material source to produce the composite material.

[0027] Accordingly, the polymer is modified into a polymer matrix having a three-dimensional network structure, thereby providing a composite material in which the weight ratio of the heat-absorbing flame-retardant material and the flame-retardant and heat-dissipating multifunctional material relative to the polymer matrix is ​​maximized.

[0028] The above heat-absorbing flame-retardant material (e.g., magnesium hydroxide) can suppress flames by absorbing heat above a reference temperature and decomposing into oxidizing substances and water vapor, thereby reducing the surrounding temperature. Additionally, the above flame-retardant and heat-dissipating multifunctional material (e.g., expanded graphite) can prevent fires by releasing heat above a reference temperature and expanding at the same time, thereby blocking oxygen from entering from the outside.

[0029] The weight ratio of the heat-endothermic flame-retardant material and the flame-retardant and heat-dissipating multifunctional material within the polymer matrix of the composite material is increased, thereby improving the heat dissipation and flame-retardant properties of the composite material. As a result, the composite material can be applied to a battery module.

[0030] Accordingly, when the above composite material is applied to the battery module, if a fire occurs in the battery module at a temperature above a reference temperature, the heat-absorbing flame-retardant material of the composite material absorbs heat to suppress the flame, and the flame-retardant and heat-dissipating multifunctional material releases heat and expands at the same time to block oxygen entering from the outside, thereby facilitating the initial suppression of the fire. Brief explanation of the drawing

[0031] FIG. 1 is a flowchart for explaining a method for manufacturing a composite material according to an embodiment of the present invention. FIG. 2 is a drawing for explaining a polymer, a heat-absorbing flame-retardant material, and a flame-retardant and heat-dissipating multifunctional material according to an embodiment of the present invention. FIG. 3 is a diagram illustrating a polymer matrix according to an embodiment of the present invention. FIG. 4 is a drawing for explaining a method of preparing a composite material source by mixing a polymer, an endothermic flame-retardant material, and a flame-retardant and heat-dissipating multifunctional material according to an embodiment of the present invention. FIG. 5 is a drawing illustrating a method for manufacturing a composite material by applying pressure to a composite material source according to an embodiment of the present invention. FIG. 6 is a drawing for explaining a battery module according to a first application example of the present invention. FIG. 7 is a drawing for explaining a battery module according to a second application example of the present invention. FIG. 8 is a drawing for explaining a battery module according to a third application example of the present invention. FIG. 9 is a drawing for explaining a battery module according to a first variation of the present invention. FIG. 10 is a drawing for explaining a battery module according to a second variation of the present invention. FIG. 11 is a drawing for explaining a heat-absorbing flame-retardant material and a flame-retardant and heat-dissipating multifunctional material of a composite material within a battery module according to an example of application of the present invention. Figure 12 is a photograph of the manufacturing process of a composite material according to Experimental Example 1 of the present invention. Figure 13 (a) is a photograph of a composite material source according to Experimental Example 1 of the present invention. Figures 13 (b) and (c) are photographs of a composite material source according to an experimental variation of the present invention. Figure 14 is an SEM image of a composite material according to Experimental Example 1 of the present invention. FIG. 15 is a graph for comparing the thermogravimetric analysis results of a polymer, an endothermic flame retardant material, and a composite material according to Experimental Example 1 of the present invention. FIG. 16 is a photograph of the UL 94 test process for evaluating the fire safety of a composite material according to experimental examples of the present invention. FIG. 17 is a graph for comparing the thermal conductivity of composite materials according to experimental examples of the present invention. Specific details for implementing the invention

[0032] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. However, the technical concept of the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosed content is thorough and complete and to ensure that the concept of the present invention is sufficiently conveyed to those skilled in the art.

[0033] In this specification, when a component is described as being on another component, it means that it may be formed directly on the other component or that a third component may be interposed between them. Additionally, in the drawings, the thicknesses of the films and regions are exaggerated for the effective description of the technical content.

[0034] Additionally, although terms such as first, second, third, etc., have been used to describe various components in the various embodiments of this specification, these components should not be limited by such terms. These terms are used merely to distinguish one component from another. Accordingly, what is referred to as the first component in one embodiment may be referred to as the second component in another embodiment. Each embodiment described and illustrated herein also includes its complementary embodiment. Furthermore, in this specification, "and / or" is used to mean including at least one of the components listed before and after it.

[0035] In the specification, singular expressions include plural expressions unless the context clearly indicates otherwise. Furthermore, terms such as "include" or "have" are intended to specify the existence of the features, numbers, steps, components, or combinations thereof described in the specification, and should not be understood as excluding the existence or addition of one or more other features, numbers, steps, components, or combinations thereof. Additionally, in this specification, "connection" is used to include both indirectly connecting multiple components and directly connecting them.

[0036] Furthermore, in describing the present invention below, if it is determined that a detailed description of related known functions or configurations could unnecessarily obscure the essence of the invention, such detailed description will be omitted.

[0038] FIG. 1 is a flowchart for explaining a method for manufacturing a composite material according to an embodiment of the present invention, FIG. 2 is a diagram for explaining a polymer, an endothermic flame-retardant material, and a flame-retardant and heat-dissipating multifunctional material according to an embodiment of the present invention, FIG. 3 is a diagram for explaining a polymer matrix according to an embodiment of the present invention, FIG. 4 is a diagram for explaining a method for manufacturing a composite material source by mixing a polymer, an endothermic flame-retardant material, and a flame-retardant and heat-dissipating multifunctional material according to an embodiment of the present invention, and FIG. 5 is a diagram for explaining a method for manufacturing a composite material by applying pressure to a composite material source according to an embodiment of the present invention.

[0039] Referring to FIGS. 1 and 2, a polymer (100), an endothermic flame-retardant material (200), and a flame-retardant and heat-dissipating multifunctional material (300) are prepared (S110).

[0040] The polymer (100) may have a first glass transition temperature and a second glass transition temperature higher than the first glass transition temperature. For example, it may be polytetrafluoroethylene. For example, the first glass transition temperature may be 19°C. For example, the second glass transition temperature may be 30°C. And, as described below, the polymer (100) may be deformed into a polymer matrix (110) by a shear force applied above the first glass temperature.

[0041] The heat-absorbing flame-retardant material (200) can absorb heat above a reference temperature and decompose into an oxidizing material (210) and water vapor. As a result, the heat-absorbing flame-retardant material (200) can reduce the ambient temperature and suppress the flame. For example, the heat-absorbing flame-retardant material (200) may be any one of magnesium hydroxide, aluminum hydroxide, antimony trioxide, or antimony pentoxide. Specifically, if the heat-absorbing flame-retardant material (200) is magnesium hydroxide, the oxidizing material (210) may be magnesium oxide.

[0042] The flame-retardant and heat-dissipating multifunctional material (300) has a higher resistance to flames than the standard and can easily release heat due to a higher thermal conductivity than the standard. In addition, the flame-retardant and heat-dissipating multifunctional material (300) can expand while releasing heat at a temperature above the standard temperature, thereby blocking oxygen from entering from the outside. As a result, the flame-retardant and heat-dissipating multifunctional material (300) can prevent fire. For example, the flame-retardant and heat-dissipating multifunctional material (300) may be any one of carbon nanotubes, expandable graphite (graphene), or carbon black.

[0043] Referring to FIGS. 2 and 3, the polymer (100) is deformed into the polymer matrix (110) by the applied shear force at a first temperature.

[0044] As described above, the polymer (100) can undergo a phase transition by the shear force applied at the first temperature and be transformed into the polymer matrix (110) having a three-dimensional network structure. For example, the first temperature may be at least the first glass transition temperature of the polymer. For example, the shear force may be 50 Nm or less.

[0045] Referring to FIGS. 1 and 4, the polymer (100), the heat-endothermic flame-retardant material (200), and the flame-retardant and heat-dissipating multifunctional material (300) are mixed at the first temperature while applying the shear force to produce a composite material source (400) (S120).

[0046] As described above, the polymer (100) can be transformed into the polymer matrix (110) having a three-dimensional network structure by the shear force at the first temperature. Accordingly, the heat-endorsing flame retardant material (200) and the flame-retardant and heat-dissipating multifunctional material (300) can be substantially uniformly dispersed within the polymer matrix (110). Accordingly, the composite material source (400) in which the heat-endorsing flame retardant material (200) and the flame-retardant and heat-dissipating multifunctional material (300) are substantially uniformly dispersed within the polymer matrix (110) can be manufactured. Furthermore, since the polymer matrix (110) has a three-dimensional network structure, the weight ratio of the heat-endorsing flame retardant material (200) and the flame-retardant and heat-dissipating multifunctional material (300) that the polymer matrix (110) can accommodate can be increased compared to the polymer (100). As a result, the weight ratio of the heat-absorbing flame-retardant material (200) and the flame-retardant and heat-dissipating multifunctional material (300) in the composite material source (400) increases, thereby improving the heat dissipation and flame-retardant properties of the composite material (500) described later. For example, with respect to the composite material source (400), the weight ratio of the heat-absorbing flame-retardant material (200) and the flame-retardant and heat-dissipating multifunctional material (300) may be 95 wt%, and the weight ratio of the polymer matrix (110) may be 5 wt%.

[0047] In addition, the weight ratio of the polymer matrix (110) to the composite material source (400) can be controlled to 5 wt% or more. When the weight ratio of the polymer matrix (110) is controlled to 5 wt% or more and pressure (above the reference pressure) is applied, the processing characteristics and molding characteristics of the composite material source (400) can be improved. As a result, the composite material (500) can be easily manufactured. Conversely, when the weight ratio of the polymer matrix (110) is controlled to less than 5 wt% and pressure (above the reference pressure) is applied, the processing characteristics and molding characteristics of the composite material source (400) may be reduced. As a result, it may be difficult to manufacture the composite material (500).

[0048] Accordingly, with respect to the composite material source (400), the weight ratio of the polymer matrix (110) is controlled to be 5 wt% or more and pressure (above the reference pressure) is applied to improve the processing and molding characteristics of the composite material source (400), thereby allowing the composite material (500) to be easily manufactured with excellent flame and heat dissipation characteristics and, at the same time, excellent processing and molding characteristics.

[0049] In addition, a stirrer may be used as a method to apply the above shear force. For example, the stirrer may be any one of a haake mixer, a ball mill, a high-speed mixer, or an internal mixer. For example, the stirring speed may be controlled to 500 rpm or more to apply the above-described shear force (500 Nm or more).

[0050] Referring to FIGS. 1 and FIGS. 5, the composite material (500) is manufactured by applying a first pressure to the composite material source (400) (S130).

[0051] At the first temperature, the first pressure is applied to the composite material source (400) to produce the composite material (500) in which the bonding strength between the polymer matrix (110) of the composite material source (400), the heat-endothermic flame-retardant material (200) within the polymer matrix (110), and the flame-retardant and heat-dissipating multifunctional material (300) is enhanced. For example, the first pressure may be 10 Pa to 50 MPa. For example, the method of applying the first pressure to the composite material source (400) may utilize any one of a mortar and pestle, a roll mill, or a press. For example, the form of the manufactured composite material (500) may be a film.

[0052] In conclusion, the composite material (500) may include the polymer matrix (110) having a three-dimensional network structure, the heat-absorbing flame-retardant material (200) dispersed within the polymer matrix (110), and the flame-retardant and heat-dissipating multifunctional material (300) dispersed within the polymer matrix (110).

[0053] Specifically, for the composite material (500), the weight ratio of the polymer matrix (110) may be 5 wt% or less, and the weight ratio of the heat-absorbing flame-retardant material (200) and the flame-retardant and heat-dissipating multifunctional material (300) may be 95 wt% or less. Accordingly, the composite material (500) can maximize the functional materials (200, 300) due to the three-dimensional network structure of the polymer matrix (110) compared to conventional composite materials.

[0054] As described above, the heat-absorbing flame-retardant material (200) can absorb heat above a reference temperature and decompose into the oxidizing material (210) and water vapor. As a result, the heat-absorbing flame-retardant material (200) can reduce the ambient temperature, thereby suppressing the flame. Furthermore, the flame-retardant and heat-dissipating multifunctional material (300) has a higher resistance to flame than the reference temperature and can easily release heat due to a higher thermal conductivity than the reference temperature. In addition, the flame-retardant and heat-dissipating multifunctional material (300) can expand while releasing heat above the reference temperature, thereby blocking oxygen from entering from the outside. As a result, the flame-retardant and heat-dissipating multifunctional material (300) can prevent fire.

[0055] Due to the three-dimensional network structure of the polymer matrix (110), the weight ratio of the heat-absorbing flame-retardant material (200) and the flame-retardant and heat-dissipating multifunctional material (300) within the composite material (500) is increased, so that the composite material (500) can have improved heat dissipation and flame-retardant properties. As a result, the composite material (500) can be applied to a battery module.

[0056] And, the method for manufacturing the composite material (500) according to an embodiment of the present invention may include, as described above, the step of manufacturing the composite material source (400) by mixing the polymer (100), the heat-endothermic flame-retardant material (200), and the flame-retardant and heat-dissipating multifunctional material (300) at the first temperature while applying the shear force, and the step of manufacturing the composite material (500) by applying the first pressure to the composite material source.

[0057] Accordingly, the process for manufacturing the composite material (500) can be simplified, thereby shortening the manufacturing time of the composite material (500). As a result, the manufacturing cost of the composite material (500) can be reduced, making it easier to mass-produce the composite material (500).

[0059] FIG. 6 is a drawing for explaining a battery module according to a first application example of the present invention.

[0060] Referring to FIGS. 1 to 5, the composite material (500) is provided in which the weight ratio of the flame-retardant and heat-dissipating multifunctional material (300) of the composite material (500) is controlled to 20 wt% or less.

[0061] Referring to FIG. 6, the composite material (500) can be applied to the battery module.

[0062] Accordingly, the battery module may include the composite material (500), a case (700) surrounded by the composite material (500), and a battery cell (600) surrounded by the case (700). In other words, the battery module may include the composite material (500), the case (700) disposed within the composite material (500), and the battery cell (600) disposed within the case. That is, the composite material (500) may be disposed on the outermost surface of the battery module.

[0063] When the weight ratio of the flame-retardant and heat-dissipating multifunctional material (300) of the composite material (500) is controlled to 20 wt% or less, the electrical conductivity of the flame-retardant and heat-dissipating multifunctional material (300) is less than or equal to the reference electrical conductivity, so that a short circuit can be prevented between the battery module and the battery module adjacent to the battery module.

[0064] In contrast, if the weight ratio of the flame-retardant and heat-dissipating multifunctional material (300) of the composite material (500) is controlled to be 20 wt% or more, the electrical conductivity of the flame-retardant and heat-dissipating multifunctional material (300) exceeds the reference electrical conductivity, and a short circuit may occur between the battery module and the battery module adjacent to the battery module.

[0065] Accordingly, when the composite material (500) is placed at the outermost edge of the battery module, the weight ratio of the flame-retardant and heat-dissipating multifunctional material (300) of the composite material (500) can be controlled to 20 wt% or less to prevent short circuits between adjacent battery modules.

[0067] FIG. 7 is a drawing for explaining a battery module according to a second application example of the present invention.

[0068] Referring to FIGS. 1 to 5, the composite material (500) is provided in which the weight ratio of the flame-retardant and heat-dissipating multifunctional material (300) of the composite material (500) is controlled to be 40 wt% or more.

[0069] Referring to FIG. 7, the composite material (500) can be applied to a battery module.

[0070] Accordingly, the battery module may include the composite material (500), a battery cell (600) surrounded by the composite material (500), and a case (700) surrounding the composite material (500). In other words, the battery module may include the case (700), the composite material (500) disposed within the case (700), and the battery cell (600) disposed within the composite material (500). That is, the case (700) may be disposed at the outermost edge of the battery module. Thus, a short circuit between the battery module and a battery module adjacent to the battery module can be prevented.

[0071] When the weight ratio of the flame-retardant and heat-dissipating multifunctional material (300) of the composite material (500) is controlled to 40 wt% or more, the heat transfer path of the flame-retardant and heat-dissipating multifunctional material (300) increases at a reference temperature, thereby improving the heat dissipation characteristics that release heat. As a result, the thermal runaway phenomenon in which the temperature of the battery module rises sharply can be suppressed. Furthermore, at a temperature above the reference temperature, the flame-retardant and heat-dissipating multifunctional material (300) expands while releasing heat to block oxygen entering from the outside, thereby preventing fire. In addition, if a fire occurs in the battery module at a temperature above the reference temperature, the toxic gas caused by the fire is captured by the expanded flame-retardant and heat-dissipating multifunctional material (300), thereby minimizing the leakage of toxic gas.

[0073] FIG. 8 is a drawing for explaining a battery module according to a third application example of the present invention.

[0074] Referring to FIGS. 1 to 5, the composite material (500) is provided in which the weight ratio of the flame-retardant and heat-dissipating multifunctional material (300) of the composite material (500) is controlled to be 40 wt% or more.

[0075] Referring to FIG. 8, the composite material (500) can be applied to a battery module.

[0076] Accordingly, the battery module may include the composite material (500), a first case (710) surrounded by the composite material (500), a battery cell (600) surrounded by the first case (710), and a second case (720) surrounding the composite material (500). In other words, the battery module may include the first case (700), the composite material (500) disposed within the first case (710), the second case (720) disposed within the composite material (500), and the battery cell (600) disposed within the second case (720). That is, the second case (720) may be disposed at the outermost edge of the battery module. Accordingly, a short circuit between the battery module and a battery module adjacent to the battery module can be prevented.

[0077] When the weight ratio of the flame-retardant and heat-dissipating multifunctional material (300) of the composite material (500) is controlled to 40 wt% or more, the heat transfer path of the flame-retardant and heat-dissipating multifunctional material (300) increases at a reference temperature, thereby improving the heat dissipation characteristics that release heat. As a result, the thermal runaway phenomenon in which the temperature of the battery module rises sharply can be suppressed. Furthermore, at a temperature above the reference temperature, the flame-retardant and heat-dissipating multifunctional material (300) expands while releasing heat to block oxygen entering from the outside, thereby preventing fire. In addition, if a fire occurs in the battery module at a temperature above the reference temperature, the toxic gas caused by the fire is captured by the expanded flame-retardant and heat-dissipating multifunctional material (300), thereby minimizing the leakage of toxic gas.

[0079] Unlike the first application example of the present invention described above, according to the first modified application example of the present invention, a first composite material and a second composite material having a higher weight ratio of flame-retardant and heat-dissipating multifunctional materials than the first composite material can be applied to the battery module to prevent short circuits and fires in the battery module. A battery module according to the first modified application example of the present invention is described below with reference to FIG. 9.

[0080] FIG. 9 is a drawing for explaining a battery module according to a first variation of the present invention.

[0081] Referring to FIGS. 1 to 5, a first composite material (510) is provided in which the weight ratio of the flame-retardant and heat-dissipating multifunctional material (300) of the composite material (500) is controlled to 20 wt% or less. Then, a second composite material (520) is provided in which the weight ratio of the flame-retardant and heat-dissipating multifunctional material (300) is controlled to 40 wt% or more so that the weight ratio of the flame-retardant and heat-dissipating multifunctional material (300) is higher than that of the first composite material (510).

[0082] Referring to FIG. 9, the first composite material (510) and the second composite material (520) can be applied to a battery module.

[0083] Accordingly, the battery module may include the first composite material (510), the second composite material (520) surrounded by the composite material (510), the case (700) surrounded by the second composite material (520), and the battery cell (600) surrounded by the case (700). In other words, the battery module may include the first composite material (510), the second composite material (520) disposed within the first composite material (510), the case (700) disposed within the second composite material (520), and the battery cell (600) disposed within the case (700). That is, the first composite material (510) may be disposed at the outermost edge of the battery module.

[0084] When the weight ratio of the flame-retardant and heat-dissipating multifunctional material (300) of the first composite material (510) is controlled to 20 wt% or less, the electrical conductivity of the flame-retardant and heat-dissipating multifunctional material (300) is less than or equal to the reference electrical conductivity, so that a short circuit can be prevented between the battery module and the battery module adjacent to the battery module.

[0085] In contrast, if the weight ratio of the flame-retardant and heat-dissipating multifunctional material (300) of the first composite material (510) is controlled to be 20 wt% or more, the electrical conductivity of the flame-retardant and heat-dissipating multifunctional material (300) exceeds the reference electrical conductivity, and a short circuit may occur between the battery module and the battery module adjacent to the battery module.

[0086] Accordingly, when the first composite material (510) is placed at the outermost edge of the battery module, the weight ratio of the flame-retardant and heat-dissipating multifunctional material (300) of the first composite material (510) can be controlled to 20 wt% or less to prevent short circuits between adjacent battery modules.

[0087] In addition, when the weight ratio of the flame-retardant and heat-dissipating multifunctional material (300) of the second composite material (520) is controlled to 40 wt% or more, the heat transfer path of the flame-retardant and heat-dissipating multifunctional material (300) increases, thereby improving the heat dissipation characteristics that release heat. As a result, the thermal runaway phenomenon in which the temperature of the battery module rises sharply can be suppressed. Furthermore, above a reference temperature, the flame-retardant and heat-dissipating multifunctional material (300) expands while releasing heat to block oxygen entering from the outside, thereby preventing fire. Moreover, if a fire occurs in the battery module above a reference temperature, the toxic gas caused by the fire is captured by the expanded flame-retardant and heat-dissipating multifunctional material (300), thereby minimizing the leakage of toxic gas.

[0088] Accordingly, when the second composite material (520) is placed within the first composite material (510), the weight ratio of the flame-retardant and heat-dissipating multifunctional material (300) of the second composite material (520) can be controlled to 40 wt% or more to prevent fire and toxic gas emissions from the battery module.

[0090] Unlike the second application example of the present invention described above, according to the second modified application example of the present invention, a third composite material and a fourth composite material having a lower weight ratio of flame-retardant and heat-dissipating multifunctional material than the third composite material can be applied to a battery module so as to improve heat dissipation efficiency and block the inflow of external oxygen. A battery module according to the second modified application example of the present invention is described below with reference to FIG. 10.

[0091] FIG. 10 is a drawing for explaining a battery module according to a second variation of the present invention.

[0092] Referring to FIGS. 1 to 5, a third composite material (530) is provided in which the weight ratio of the flame-retardant and heat-dissipating multifunctional material (300) of the composite material (500) is controlled to 40 wt% or more, and the weight ratio of the heat-absorbing flame-retardant material (200) is controlled to 55 wt% or less. Additionally, a fourth composite material (540) is provided in which the weight ratio of the flame-retardant and heat-dissipating multifunctional material (300) of the composite material (500) is controlled to 20 wt% or less, and the weight ratio of the heat-absorbing flame-retardant material (200) is controlled to 75 wt% or more.

[0093] Referring to FIG. 10, the third composite material (530) and the third composite material (540) can be applied to a battery module.

[0094] Accordingly, the battery module may include the third composite material (530), the fourth composite material (540) surrounded by the third composite material (530), the battery cell (600) surrounded by the fourth composite material (540), and a case (700) surrounding the third composite material (530). In other words, the battery module may include the fourth composite material (540) disposed within the case (700), the third composite material (530) disposed within the fourth composite material (540), and the battery cell (600) disposed within the third composite material.

[0095] The fourth composite material (540) may have a higher weight ratio of the heat-absorbing flame-retardant material (200) than the third composite material (530). Therefore, the fourth composite material (540) may have a higher heat-absorbing characteristic than the third composite material (530). As a result, flames may be prevented.

[0096] In addition, the third composite material (530) may have a higher weight ratio of the flame-retardant and heat-dissipating multifunctional material (200) than the fourth composite material (540). Accordingly, the third composite material (530) may have a higher characteristic of blocking oxygen entering from the outside with the flame-retardant and heat-dissipating multifunctional material (300) than the fourth composite material (540). As a result, fire can be prevented.

[0097] Accordingly, at a temperature above the reference temperature, the flame-retardant and heat-dissipating multifunctional material (300) of the third composite material (530) expands while releasing heat to block oxygen entering from the outside, thereby preventing fire, and at the same time, the heat-absorbing flame-retardant material (200) of the fourth composite material (530) absorbs heat to prevent flames, and the temperature rise of the battery module can be minimized.

[0099] FIG. 11 is a drawing for explaining a heat-absorbing flame-retardant material and a flame-retardant and heat-dissipating multifunctional material of a composite material within a battery module according to an example of application of the present invention.

[0100] Referring to FIGS. 1 to 5, the weight ratio of the polymer matrix (110) of the composite material (500) is controlled to be 5 wt% or more, and the weight ratio of the heat-absorbing flame-retardant material (200) and the flame-retardant and heat-dissipating multifunctional material (300) is controlled to be 95 wt% or less.

[0101] Referring to FIGS. 6 and 11, the composite material (500) can be applied to a battery module.

[0102] Accordingly, the battery module may include a composite material (500), a case (700) surrounded by the composite material (500), and a battery cell (600) surrounded by the case (700). In other words, it may include the composite material (500), the case (700) disposed within the composite material (500), and the battery cell (600) surrounded by the case (700).

[0103] As described above, the heat-absorbing flame-retardant material (200) can absorb heat above a reference temperature and decompose into the oxidizing material (210) and water vapor. As a result, the heat-absorbing flame-retardant material (200) can reduce the ambient temperature and suppress the flame. Additionally, the flame-retardant and heat-dissipating multifunctional material (300) can release heat above a reference temperature and expand to block oxygen entering from the outside.

[0104] Accordingly, when a fire occurs in the battery module at a temperature above the reference temperature, the heat-absorbing flame-retardant material (200) of the composite material (500) absorbs heat to suppress the flame, and the flame-retardant and heat-dissipating multifunctional material (300) blocks oxygen from entering from the outside, making it easy to suppress the fire in its early stages.

[0106] Hereinafter, specific experimental examples and the results of characteristic evaluation of the composite material according to the embodiments of the present invention are described.

[0108] Composite material manufacturing according to Experimental Example 1

[0109] Polytetrafluoroethylene was prepared as a polymer material, magnesium hydroxide as a heat-endothermic flame retardant material, and expandable graphite (graphene) as a flame-retardant and heat-dissipating multifunctional material.

[0110] The above polymer material, the above heat-absorbing flame-retardant material, and the above flame-retardant and heat-dissipating multifunctional material were provided to a high shear mixer in a weight ratio of 5:90:5 and stirred at 30°C for 1 minute to prepare a composite material source.

[0111] The above composite material source was supplied to a mortar and pestle to apply primary pressure. Then, secondary pressure was applied using a roll mill to produce the composite material according to Experimental Example 1.

[0113] Composite material manufacturing according to Experimental Example 2

[0114] A composite material according to Experimental Example 2 was prepared in the same manner as Experimental Example 1, except that the above polymer material, the above heat-absorbing flame-retardant material, and the above flame-retardant and heat-dissipating multifunctional material were provided to a high-speed mixer in a weight ratio of 5:85:10.

[0116] Composite material manufacturing according to Experimental Example 3

[0117] A composite material according to Experimental Example 3 was prepared in the same manner as Experimental Example 1, except that the above polymer material, the above heat-absorbing flame-retardant material, and the above flame-retardant and heat-dissipating multifunctional material were provided to a high-speed mixer in a weight ratio of 5:80:15.

[0119] Composite material manufacturing according to Experimental Example 4

[0120] A composite material according to Experimental Example 4 was prepared in the same manner as Experimental Example 1, except that the above polymer material, the above heat-absorbing flame-retardant material, and the above flame-retardant and heat-dissipating multifunctional material were provided to a high-speed mixer in a weight ratio of 5:75:20.

[0122] division Polymer (wt%) Heat-absorbing flame retardant (wt%) Flame-retardant and heat-dissipating multifunctional material (wt%) Stirring temperature (°C) Experiment Example 1 5 90 5 30 Experiment Example 2 5 85 10 30 Experiment Example 3 5 80 15 30 Experiment Example 4 5 75 20 30

[0124] Figure 12 is a photograph of the manufacturing process of a composite material according to Experimental Example 1 of the present invention.

[0125] Referring to FIG. 12(a), a composite material source according to Experimental Example 1 was photographed. Referring to FIG. 12(b), the composite material source was fed into a mortar and pestle to apply primary pressure, after which a photograph was taken. Referring to FIG. 12(c), the composite material source was fed into a roll mill to apply secondary pressure, and a composite material manufactured in the form of a film (2 cm x 2 cm) was photographed. Referring to FIG. 12(d), the composite material source was subjected to pressure using a hand to manufacture a composite material in a spherical shape, which was then photographed.

[0126] As can be seen in Figures 12 (a) to (d), when pressure is applied to the composite material source according to Experimental Example 1, it can be seen that the processing and molding of the composite material are easy.

[0128] FIG. 13 (a) is a photograph of a composite material source according to Experimental Example 1 of the present invention, and FIG. 13 (b) and (c) are photographs of a composite material source according to experimental modified examples of the present invention.

[0129] Referring to FIG. 13(a), the composite material source according to Experimental Example 1 was fed into a mortar and pestle, and a photograph was taken after applying primary pressure. Referring to FIG. 13(b), a composite material source was prepared in the same manner as Experimental Example 1, except that the temperature was controlled to 3°C to 5°C during the process of feeding a polymer, an endothermic flame-retardant material, and a flame-retardant and heat-dissipating multifunctional material into a high-speed mixer and stirring. Then, the composite material source was fed into a mortar and pestle, and a photograph was taken after applying primary pressure. Referring to FIG. 13(c), a composite material source was prepared in the same manner as Experimental Example 1, except that the weight ratio of the polymer material was changed from 5 wt% to 3 wt%. Then, the composite material source was fed into a mortar and pestle, and a photograph was taken after applying primary pressure.

[0130] As can be seen in FIG. 13 (a) to (c), in the process of providing the polymer, the heat-endothermic flame-retardant material, and the flame-retardant and heat-dissipating multifunctional material to a high-speed mixer and stirring, it can be seen that the temperature must be controlled to be above the first glass transition temperature (19°C) of the polymer. Conversely, if the temperature is controlled to be below the first glass transition temperature (3°C to 5°C) of the polymer, it can be seen that processing and molding into the composite material is difficult even when pressure is applied to the composite material source.

[0131] Furthermore, it can be seen that during the process of providing the polymer, the heat-endothermic flame-retardant material, and the flame-retardant and heat-dissipating multifunctional material to a high-speed mixer and stirring, the weight ratio of the polymer must be controlled to be greater than or equal to a standard weight ratio (5 wt%). Conversely, if the weight ratio of the polymer is controlled to be less than the standard weight ratio (3 wt%), it can be seen that processing and molding into the composite material is difficult even when pressure is applied to the composite material source.

[0132] In conclusion, it can be seen that in the process of providing the polymer, the heat-endothermic flame-retardant material, and the flame-retardant and heat-dissipating multifunctional material to a high-speed mixer and stirring, the temperature must be controlled to be at least the first glass transition temperature (19°C) of the polymer, and the weight ratio of the polymer must be controlled to be at least the reference weight ratio (5 wt%).

[0134] Figure 14 is an SEM image of a composite material according to Experimental Example 1 of the present invention.

[0135] Referring to Fig. 14, the composite material according to Experimental Example 1 was cross-cut and photographed using SEM.

[0136] As can be seen in Fig. 14, it can be seen that the heat-absorbing flame-retardant material and the flame-retardant and heat-dissipating multifunctional material are uniformly dispersed within the polymer matrix of the composite material according to Experimental Example 1.

[0137] Accordingly, it can be seen that when a shear force is applied to the polymer by a high-speed mixer at a first glass transition temperature (19°C) or higher, the polymer is transformed into a polymer matrix having a three-dimensional network structure. Accordingly, it can be seen that during the process of mixing the polymer, the heat-endorsing flame retardant material, and the flame-retardant and heat-dissipating multifunctional material, the heat-endorsing flame retardant material and the flame-retardant and heat-dissipating multifunctional material are uniformly dispersed within the polymer matrix.

[0139] FIG. 15 is a graph for comparing the thermogravimetric analysis results of a polymer, an endothermic flame retardant material, and a composite material according to Experimental Example 1 of the present invention.

[0140] Referring to FIG. 15, the thermogravimetric change of the polymer, the heat-endothermic flame-retardant material, and the composite material according to Experimental Example 1 was measured using a thermogravimetric analyzer while providing a temperature of up to 600°C.

[0141] As can be seen in Fig. 15, the heat-absorbing flame retardant material (Mg(OH)2) begins to decompose into oxidized heat-absorbing flame retardant material (MgO, 70 wt%) and water vapor (H2O, 30 wt%) at about 330°C.

[0142] And, it can be seen that the above polymer begins to decompose at about 500°C and is substantially, completely decomposed at about 600°C.

[0143] On the other hand, it can be seen that the heat-absorbing flame-retardant material of the composite material according to Experimental Example 1 begins to decompose at approximately 330°C and exhibits a weight loss of approximately 30 wt% up to 600°C. Therefore, it can be seen that the composite material can withstand heat provided up to 600°C or higher.

[0144] Accordingly, when the above composite material is applied to a battery module, it can be seen that fire suppression of the battery module is easy in the event of a fire in the battery module.

[0146] FIG. 16 is a photograph of the UL 94 test process for evaluating the fire safety of a composite material according to experimental examples of the present invention.

[0147] Referring to FIG. 16(a), a photograph was taken immediately after applying a flame to the composite material according to the experimental examples (Experimental Examples 1 to 4). Referring to FIG. 16(b), a photograph was taken 5 seconds after applying a flame to the composite material according to the experimental examples. Referring to FIG. 16(c), a photograph was taken 10 seconds after applying a flame to the composite material according to the experimental examples. Referring to FIG. 16(d), a photograph was taken after removing the flame from the composite material according to the experimental examples. The U 94 test results of the composite material according to the experimental examples are summarized in below.

[0148] As can be seen in FIGS. 16 (a) to (d) and Table 2, the composite materials according to the experimental examples (Experimental Examples 1 to 4) have a limiting oxygen concentration index of 95% or higher and a total heat release rate of 1 MJ / m² in the UV 94 test. 2 It can be seen that it is less than V-0, which is the highest grade among UV 94 test grades. Therefore, it can be seen that the composite material according to the experimental examples has fire safety.

[0150] division Limiting Oxygen Index (%) U94 test grade Total heat release rate (MJ / m²) 2 ) Experiment Example 1 95% or more V-0 0.25 Experiment Example 2 95% or more V-0 0.29 Experiment Example 3 95% or more V-0 0.41 Experiment Example 4 95% or more V-0 0.66

[0152] FIG. 17 is a graph for comparing the thermal conductivity of composite materials according to experimental examples of the present invention.

[0153] Referring to FIG. 17, the thermal conductivity of the composite material according to Experimental Examples 1 to 4 was measured.

[0154] As can be seen in Fig. 17, the thermal conductivity of the composite material according to Experimental Example 4 is the highest at approximately 1.6 W / mk.

[0155] This factor is interpreted to be due to the fact that the weight ratio of the flame-retardant and heat-dissipating multifunctional material (expanded graphite) of the composite material according to Experimental Example 4 is the highest among the experimental examples at 20 wt%.

[0156] Therefore, it can be seen that the flame retardant and heat dissipation properties of the composite material can be controlled by manufacturing the composite material by controlling the weight ratio of the flame retardant and heat dissipation multifunctional material and the heat-absorbing flame retardant material.

[0158] Although the present invention has been described in detail using preferred embodiments, the scope of the invention is not limited to specific embodiments and should be interpreted by the appended claims. Furthermore, those skilled in the art will understand that many modifications and variations are possible without departing from the scope of the invention. Explanation of the symbols

[0159] 100: Polymer 110: Polymer Matrix 200: Heat-absorbing flame retardant 300: Flame-retardant and heat-dissipating multifunctional material 400: Composite material source 500: Composite materials 600: Battery cell 700: Case

Claims

Claim 1 A first composite material; a second composite material surrounded by the first composite material; a case surrounded by the second composite material; and a battery cell surrounded by the case, wherein the first composite material and the second composite material comprise: a polymer matrix having a three-dimensional network structure; and an endothermic flame-retardant material dispersed within the polymer matrix that absorbs heat and suppresses flames above a reference temperature. A battery module comprising a flame-retardant and heat-dissipating multifunctional material dispersed within the polymer matrix and expanding to block incoming oxygen while releasing heat at a reference temperature or higher, wherein the weight ratio of the flame-retardant and heat-dissipating multifunctional material of the first composite material is smaller than the weight ratio of the flame-retardant and heat-dissipating multifunctional material of the second composite material, wherein the reference temperature is 330°C or higher, wherein the polymer matrix comprises polytetrafluoroethylene, the heat-endothermic flame-retardant material comprises magnesium hydroxide, and the flame-retardant and heat-dissipating multifunctional material comprises expandable graphite (graphene). Claim 2 A battery module according to claim 1, wherein the weight ratio of the flame-retardant and heat-dissipating multifunctional material of the first composite material is 20 wt% or less, the weight ratio of the flame-retardant and heat-dissipating multifunctional material of the second composite material is 40 wt% or more, and the weight ratio of the polymer matrix of the first composite material and the second composite material is 5 wt% each. Claim 3 A battery module according to claim 2, wherein, at a reference temperature or higher, the electrical conductivity of the first composite material is reduced by the weight ratio of the flame-retardant and heat-dissipating multifunctional material of the first composite material, thereby preventing a short circuit between the battery module and the battery module adjacent to the battery module. Claim 4 A battery module according to claim 2, wherein, at a reference temperature or higher, the heat dissipation characteristics of the second composite material are enhanced by the weight ratio of the flame-retardant and heat-dissipating multifunctional material of the second composite material, thereby suppressing the thermal runaway phenomenon of the battery module. Claim 5 A battery module according to claim 4, wherein, at a temperature above the reference temperature, the second composite material expands while releasing heat due to the weight ratio of the flame-retardant and heat-dissipating multifunctional material of the second composite material, thereby blocking oxygen entering from the outside to prevent fire and capturing toxic gases to suppress the leakage of toxic gases. Claim 6 A battery module according to claim 1, wherein the weight ratio of the heat-absorbing flame-retardant material and the flame-retardant and heat-dissipating multifunctional material is 95 wt%. Claim 7 A third composite material; a fourth composite material surrounded by the third composite material; a battery cell surrounded by the fourth composite material; and a case surrounding the third composite material, wherein the third composite material and the fourth composite material comprise: a polymer matrix having a three-dimensional network structure; and an endothermic flame-retardant material dispersed within the polymer matrix that absorbs heat and suppresses flames above a reference temperature. A battery module comprising a flame-retardant and heat-dissipating multifunctional material dispersed within the polymer matrix and expanding to block incoming oxygen while releasing heat at a reference temperature or higher, wherein the weight ratio of the heat-absorbing flame-retardant material of the fourth composite material is greater than the weight ratio of the heat-absorbing flame-retardant material of the third composite material, wherein the reference temperature is 330°C or higher, wherein the polymer matrix comprises polytetrafluoroethylene, wherein the heat-absorbing flame-retardant material comprises magnesium hydroxide, and wherein the flame-retardant and heat-dissipating multifunctional material comprises expandable graphite (graphene). Claim 8 A battery module according to claim 7, wherein the weight ratio of the heat-absorbing flame-retardant material of the third composite material is 55 wt% or less, the weight ratio of the heat-absorbing flame-retardant material of the fourth composite material is 75 wt% or more, and the weight ratio of the polymer matrix of the third composite material and the fourth composite material is 5 wt% each. Claim 9 A battery module according to claim 8, wherein, at a reference temperature or higher, the fourth composite material has a higher weight ratio of the heat-absorbing flame-retardant material than the third composite material, and thus has excellent heat-absorbing properties. Claim 10 A battery module according to claim 8, wherein, at a reference temperature or higher, the third composite material has a higher weight ratio of the flame-retardant and heat-dissipating multifunctional material than the fourth composite material, and has excellent properties for blocking oxygen introduced from the outside. Claim 11 A battery module according to claim 7, wherein the temperature rise of the battery module is reduced by the third composite material and the fourth composite material.

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